Absorption refrigeration apparatus



April 29, 1941. c. c. cooNs EIAL ABSORPTION REFRIGERATION APPARATUS vFiled Dec. '30, 1936 (urlzls 6'. 6000s Rudoo/z .SiNels'on ATTORNEYPatented Apr. 29, 1941 ABSORPTION REFRIGERATION APPARATUS Curtis C.Coons, North Canton, Ohio, and Rudolph S. Nelson, Larchmont, N. Yassignors to The Hoover Company, North Canton,

n tation of Ohio Ohio, a cor- Application December 30, 1936, Serial No.118,285

36 Claims.

This invention relates to continuous absorption refrigeration apparatus,and more particularly to means for circulating fluids therein. Thisapplication is a continuation in part of our application for LettersPatent Serial No. 97,942, filed Aug. 26, 1936.

Absorption refrigeration system of the three fluid type include arefrigerant generator, an evaporator, and. an absorber as principalelements. An inert gas or pressure equalizing medium is circulatedthrough conduits interconmeeting the absorber and the evaporator, whilean absorption liquid for the refrigerant is circulated through conduitsinterconnecting the absorber and the generator. pressure equalizingmedium circulated between the absorber and evaporator is much greaterthan the volume of absorption solution circulated between the absorberand the generator. It is essential that the apparatus be provided withsome means for assuring the proper circulation of the absorption mediumin its circuit The volume of which it is subject to corrosion andclogging The refrigerant vapor must be maintained at a high temperatureto prevent its condensation and absorption by the absorption liquid. Therate of circulation varies over a wide range as it is a function of theboiler'temperature, and is accordingly dimcult to control. I

The present invention, however, entirely avoids the many disadvantagesand undesirable characteristics of the vapor lift pump, utilizes thegreat simplicity of the gas lift type of pump, and provides aconstruction which functions equally well in either a high or lowtemperature zone. This is for the reason that our pump is operated byinert gas which does not condense and is not absorbed by the absorptionliquid, The introduction of the inert gas into the absorption liquid isnot dependent upon the temperature of either thegas or the absorptionliquid, and the rate of circulation through the pump is substantiallyunaffected by wide variations in the temperature of the gas suppliedthereto. It is therefore possible to locate the pump in any part of thesolution circuit and to circulate the solution at will independently ofI the temperature of the boiler.

vention proposes to create a pressure differential in the inert gascircuit for the purpose of circulating the gas therein-at a desiredrate, and to employ this pressure differential to circulate theabsorption medium in its circuit at a desired rate which is much lessthan but substantially proportional to the rate of inert gascirculation.

A preferred manner of practicing the invention is to bleed off arelatively small portion of gas from a high pressure area in the inertgas circuit and to bubble this gas into a column of absorption liquid.The mixture of liquid and gas results in the lowering of the specificgravity of this column and the raising of the surface level of theliquid to an elevated point.

Heretofore, it has been common practice to employ a vapor lift pump forcirculating the absorption solution. This pump is operated by bubbles oirefrigerant vapor produced in the boiler. Such pumps have manydisadvantages and limitations which greatly restrict their use. Forexample, the small diameter vapor lift pump must be located in a hightemperature region in By reason of our novel arrangement of the inertgas and the absorption solution circuits, it is possible to circulateboth the inert gas and the absorption liquid at the proper respectiverates for optimum operating conditions without resorting to the use ofvalves or other restricting devices. And this is accomplished by thesimple expedient of diverting only a very small percentage of the maininert gas stream'from its normal circuit between the evaporator andabsorber. In addition to the many advantages provided by ourarrangement, as hereinabove pointed out, we have found that it alsoprovides an unusually facile method of governing and maintainingstaible. operating conditions within the system.

A second embodiment of the invention shows the solution pump as beinglocated in the enriched solution return conduit extending between thelower end of the absorber and the boiler assembly. This arrangementpermits the entire absorber to be located between the upper and lowerlimits of the boiler assembly rather than above the boiler. An unusuallycompact boiler-absorber assembly is therefore possible, and thisdesirable arrangement is achieved without sacrificing simplicity orefllciency.

It is accordingly the object of the invention to Provide a novelabsorption refrigeration system solution from reservoir 30 into an upperportion having the advantages and characteristics pointed out by way ofillustration hereinabove. Still other advantages will become apparentfrom the description taken in connection with the drawing wherein: a

Figure 1- is a diagrammatic view in elevation of one form of theinvention showing a part of the apparatus broken way: and,

Figure 2 is a diagrammatic view in elevation showing a modifiedembodiment of the invention.

Referring to the drawing in detail, and first to Figure 1, a continuousabsorption refrigeration apparatus is shown consisting of aboileranalyzer assembly 13, a rectifier R, an absorber assembly AHA", acondenser C, an evaporator E, a gas pump F, and two liquid gas liftpumps P and P", as essential elements, these elements being connected toform the complete refrigeration apparatus by various conduits some ofwhich are in heat exchange relation.

The boiler-analyzer assembly B may be constructed with a main horizontalbody portion or boiler l0, and an upstanding portion or analyzer lllocated near one end of the boiler. ,A conduit l2 extends from the topof the analyzer ll through rectifier R and then into the top of thecondenser C and serves to convey refrigerant vapor from the boiler tothe condenser. Both the rectifier and the condenser may be cooled in anysuitable manner, as by the usual heat radiating fins. The discharge end13 of the condenser extends into the top of the evaporator E.

The absorber assembly consists of two adjacent and downwardly inclinedvessels A A. This assembly is located below the evaporator E and isconnected thereto by means of conduits l4 and I5. Conduit ll leadinginto the lower end of absorber A and conduit II leading into the lowerend of absorber A. The to? portions of the two absorbers are connectedby conduit Ii terminating in a conduit [1 leading into the intake of thefan chamber is of gas pump F. An electric motor I! may be hermeticallysealed within the system and connected to drive a fan or impeller withinchamber I I. A conduit 2| serves to conduct the gas discharged by gaspump F into evaporator E, while conduit ll serves to conduct therefrigerant laden inert gas but of evaporator E. Gas conduits I4 and IIare preferably in heat exchange relation at Ii.

The absorbers A and A may be of any suitable form, and may containbaflles such as shown at 22 to retard the passage of liquid therethroughso as to increase the surface contact between the absorption fluid andthe refrigerant laden inert gas. It is important that the absorbers becooled in some manner. This may be done by means of air-cooled, heatdissipating fins is affixed to the exterior surfaces of the absorbers.

The absorption fluid circuit consists .of conduit 24 leading from thebottom of the boiler ll into the bottom portion of a U tube II. The twolegs 2 andi'l of this U tube are connected to the top portion ofabsorbers A and A respectively. u tube 25 constitutes a part of the gaslift pumps P and P, as will appear more fully hereinbelow. Conduits 28and 2! lead from the lower ends of the absorbers into a reservoir Aconduit ll conveys enriched absorption of the analyzing column ll.Conduits ii and 2| are in heat exchange at 34.

we have discovered that a miniature fan opcrating at relatively lowspeeds is capable of producing a pressure differential equivalent toseveral inches of water when operating in a gaseous medium having arelatively high 'molecular weight, as for example nitrogen, when under apressure equivalent to that used in a refrigerating system employing apressure equalizing medium. If an inert gas of low molecular weight likehydrogen is used, it is necessary to employ a fan many times larger thanis the case with a dense gas. The larger fan, of course, requires alarger motor and consumes more power than the miniature fan and motorused in our construction. The significance of the foregoing will beapparent when it is realized that for the same amount of useful work, atremendous saving in operating and construction cost may be made byemploying a dense, inert gas rather than a light gas. a

The unique advantage of generating a relatively high'pressuredifferential in a refrigerating apparatus employing a pressureequalizing medium is that the pressure may be used to operate a liquidgas lift pumpas well as to circulate the inert gas. Moreover since thevolume of absorbent solution circulated is small compared to that of thepressure equalizing medium, a small portion of the inert gas dischargedfrom the gas pump F may be used to operate the liquid gas lift'pumps Pand P for circulating the absorbent solution without increasing thepower required to operate the gas pump F by more than an insignificantamount.

The gas pump F can be controlled in any desired manner such as manuallyor automatically in accordance with temperature conditions, forinstance, in some part of the system.

The apparatus of Figure 1 operates in the following manner:

The apparatus may be charged in accordance with known practices with anysuitable fluids such as ammonia as the refrigerant, water as theabsorbent, and any dense, inert gas, such as nitrogen, which serves asthe pressure equalizing medium. The boiler contains a mixture of ammoniaand water and may be heated in any suitable manner such as by anelectric cartridge heater or by a fluid fuel burner. Vapor is liberatedfrom the solution and passes upwardly through conduit l2, rectifier R,and into the top portion of condenser C. Any water vapor which remainsin the refrigerant vapor after passing through the analyzing column llis condensed as it passes through the rectifier R and flows back intothe analyzing column II.

The ammonia vapor is condensed in the condenser C and flows downwardlyinto conduit is,

and from there into the top of the evaporator E. Flowing down throughevaporator E, the liquid ammonia evaporates in the stream of inert gasflowing through the evaporator E ther by producing refrigeration.

When the gas pump F is energized gas will be circulated between theevaporator E and absorbers A and A, thus delivering the ammoniasubstantially equal portions to legs 25 and 21 of U tube 25. P and Ptogether constitute what we prefer to call a twin gas lift pump as willbecome more apparent hereinbelow. The connections between U tubes 25and- 33 are pos'itioned somewhat below the normal level of absorptionfluid in the system and thus two liquid gas lift pumps P and P areformed. However, one pump does not function entirely independently ofthe other due to conduit 25 which interconnects the lower end of thepumps.

Assuming that fan F is started after a period of rest, the twin gas liftpump operates as follows: At first the absorption solution liquid levelwill be at rest in legs 25 and 21 and in U-tube- 33. As soon as fan Fbegins to build up the inert gas pressure in conduit 52 and U-tube 33,the liquid level will be depressed until such time as the liquid thereinis forced into legs 25 and 21. It is our observation that the gas doesnot pass simultaneously into each of the legs 25 and 21, but on thecontrary a bubble of gas passes into one leg and immediately upsets theequilibrium between the two legs so that the liquid level rises in thelighter of the two columns and falls in the heavier column. Eventually agas bubble passes into the other leg and causes the liquid column inconduit 25 to move in the opposite direction. The gas .then continues tobubble into first one leg and then the other and the liquid inconduit-.25 continues to oscillate and in such manner as to governautomatically the distribution of gas between the two legs in'equalamounts if the several pump conduits are of the same size, or in unequalamounts if the conduits are of 'diiferent sizes. It therefore followsthat the absorption solution discharges alternate from the tops of thetwo legs.

It will accordingly be obvious why we choose to term our pumping devicea twin gas lift pump which can be utilized to divide a stream of liquidor to elevate liquid to a single chamber or to two separate chambers.The oscillating piston "of liquid in conduit 25 seems to act as agovernor tending to maintain the rate of flow constant'both from thepump as a whole and from each of the respective legs.

It will therefore be understood that the gas delivered into legs 25 and21 is under a higher pressure'than the gas at the top of the absorbersinto which thelegs discharge, and that bubbles of gas and slugs ofabsorption fluid will alternately flow from the top of legs 25 and 21into the top sections of the absorbers A and A respectively. From thispoint the absorption fluid flows downwardly over baiiies 22 absorbingammonia gas passing through the absorbers in counterflow to theabsorption liquid. The enriched absorbent solution flows into receivingvessel 30 through conduits 25 and 29. Vessel 35 may be dispensed with ifdesired. From vessel 30 the relatively cool, rich fluid flows back toan.

upper portion of the analyzer column ll, after first passing in heatexchange relation at 34 with weak absorption fluid from boiler l5.-.

Theenriched absorption fluid returned to the,

analyzer immediately comes into contact with a mixture of ammonia andwater vapor. The rich absorption fluid having a lower boiling pointtemperature than the liquid from which the vapor bubbles were generatedpartially condenses the vapor. up to the enriched fluid and vaporizesammonia therefrom. That a great saving in heat is ac-v complished bythis mode of operation is at once The heat of condensation is given,near one end of the'boiler.

apparent. Not only is a relatively small proportion of absorbent vaporleft to be removed by rectifier R, but the heat which would otherwise bedissipated from the rectifier is utilized in the analyzing column toliberate additional refrigerant.

Referring now to Figure 2, it will be seen that the general arrangementis very similar to that shown in Figure 1 and comprises aboiler-analyzer assembly B, a condenser C, an evaporator E, an absorberA, a liquid gas lift pump P, and a gas pump F, as essential elements,these elements being connected by conduits to form a completerefrigeration apparatus.

The boiler-analyzer assembly B consists of a lower, horizontallyextending portion or boiler 55 and avertical analyzing colunm 5| locatedA conduit 52 leads from the top of the analyzer through the rectifler Rand into the top of condenser C. The condenser discharges into the topof evaporator E through conduit 53.

The absorber A is located below the evaporator and may be of any desiredform, the one shown being similar to one of the absorbers shown inFigure 1. evaporator E by means of gas conduits 54, 55 and 55, conduits54 and 55 preferably being in heat exchange relation at 51. A gas pump Fcomprising an electricmotor 58, and a centrifugal fan 59, serves toconnect conduits 54 and 55, it being noted that conduit 54 opens intothe intake of the fan and conduit 55 connects with the dischargethereof.

The absorption fluid circuit consists of a conduit 55 leading from thebottom of the boiler 55 to the top of the absorber A; another conduit 5|connects the bottom of the absorber with a receiving vessel \orreservoir 52. A U-shaped conduit 53 interconnects vessel 52 and anelevated gas separation vessel 54, as shown in Figure 2. Leading fromvessel 54 is a conduit 55 which conducts the enriched aqua back to anupper portion of the analyzer 5| after first passing in heat exchangerelation at 55 with weak aqua.

In order to circulate the absorption fluid in connection of conduit 51with U tube 53 should,

of course, be somewhat lower than the liquid level existing in the leftleg of U-shaped conduit 53. The liquid level in this leg will be higherthan the level in vessel 52 due to the pressure differential existingacross the gas pump F. Since vessel 54 is vented through conduit 55 tosome other part of the system, such as conduit 54, it is apparent thatthe gas pressure in conduit 51 is greater than that existing in vessel54 when the refrigerating system'is in operation. Consequently,alternate bubbles'of inert gas and slugs of absorption fiuid will formin the longer leg of U tube 53, thus causing the liquid to be elevatedinto vessel 54 in the same manner as described above in connection withgas lift pumps P and P shown in Figure 1. a

The absorber A is connected to the In this embodiment it is necessarythat the absorber be positioned below the top of the boileranalyzerassembly rather than thereabove as in the first embodiment. This is forthe reason that the absorption liquid flows by gravity from the boilerto the absorber. Accordingly, it will be manifest that this arrangementhas the very great advantage of compactnessparticularly in a verticaldirection. This feature is especially important in the application ofthe invention to household refrigerators where the space limitations forthe apparatus are very rigid.

It is thought unnecessary to go into a detailed description of the modeof operation of the modification just described since its operation willbe apparent from the description just given, and particularly in view ofthe complete description given of Figure 1. Thus it will be apparentthat refrigerant is generated in boiler 50 by the application of heatwhich refrigerant is condensedin condenser C and delivered in liquidform to the evaporator. through the evaporator E readily evaporates intothe inert gas stream and is carried away through conduit 54. The largerportion of this gaseous mixture is delivered into the lower end ofabsorber A through which it passes in counterflow to and in intimateabsorption relationship with weak absorbent medium from boiler 50. Bythe time the refrigerant inert gas mixture reaches the top of theabsorber, most of the ammonia gas has been absorbed. Relatively, pureinert gas is then returned to the evaporator through conduit 58 afterpassing in heat exchange relation with the mixture of inert gas andammonia flowing from evaporator E at 51.

A small portion of thegaseous mixture discharged from the gas pump F isled through conduit 61 and bubbled into'the left leg of U tube 63 andelevates the enriched absorbent medium into vessel 64. The gas used inthe liquid gas lift pump P, thus by-passes the absorber 'A andevaporator E flowing from gas pump F through conduits 55, 61 and 83 intovessel 64 then back to the gas pump F through conduits 68 and ll. Therich aqua flows by gravity from vessel 84 back into the upper portion ofthe analyzer 5 I.

From the foregoing, itwill be appreciated that we have devised a new andnovel refrige ation system having many advantages over systemsheretofore known. Not only is the pressure equalizing medium forciblycirculated, but the pressure differential created for this purpose isalso utilizedto circulate the absorption medium between the boiler,absorber and analyzer in a novel and heretofore unknown manner.Moreover, by reason of our construction, the flow of inert gas and ofabsorption fluid may be so proportioned relative to one another by aproper design of the various vessels that the system operates at amaximum emciency over a wide range of conditions without resort to theuse of control or restricting devices within the system.

Furthermore, it will be obvious that our system lends itself toautomatic control by the simple expedient of starting and stopp n thegas pump F. If it is desired to vary the capacity of the apparatus, itis only necessary to vary the speed of the fan and the heat supply tothe boiler. Varying the speed of the motor automatically varies the.rate of gas circulation and of absorp- The ammonia flowing While onlytwo embodiments of the invention have been shown and described herein,it is to be understood that various changes may be made in thearrangement and construction of parts without departing from the spiritof the invention or the scope of the annexed claims.

. We claim:

1. In an absorption refrigerating system, a boiler, an absorber having aplurality of sections, conduits for conveying liquid by gravity from theabsorber to the boiler and an arrangement for delivering absorptionliquid from the boiler to the absorber and for dividing the same intotwo streams, said arrangement including a twin lift gas-operated pump,and means for supplying gas thereto.

2. In an absorption refrigerating system, a boiler, an absorber, aconduit for conveying liquid from the absorber to the boiler by gravityand means for lifting the liquid fror. the boiler to a higher level forflow into the absorber, said means including a twingas lift pump andmeans for supplying gas thereto.

3. In an absorption refrigerating system, an absorber having a pluralityof chambers, means for supplying liquid to said chambers from a levelbelow the same, and fordividing the liquid between said chambers, saidmeans including a multiple discharge gas-operated pump and means forsupplying gas thereto.

4. The combination, in an absorption refrigeration system of the typeemploying a refrigerant, an absorbent therefor, and a dense inert gas,of an evaporator; a boiler having an analyzer, and an absorberpositioned above said analyzer,

; means providing a liquid circuit between said absorber, analyzer andboiler, and means providing a gas circuit between the evaporator andabsorber, a power driven fan in said gas circuit, and a connectionbetween said gas circuit and said liquid circuit whereby a portion onlyof said gas is utilized to lift the liquid to the top of the absorberfrom whence it flows by gravity through the remainder of the circuit.

5. In combination, an absorber for use in an absorption refrigerationsystem, means providing a circuit for the circulation of an absorbentliquid through the absorber, and power driven means for circulating arefrigerant-carrying dense, inert gas through the absorber, said lastmentioned means including nieans for by-passing some of said dense gasto said liquid circuit to lift the liquid from a point below the top ofthe abmrber to the top thereof whereby the ab sorbent flows by gravitythrough the remainder of the circuit.

6. The method of bringing an absorbent liquid into absorbing relationwith a dense inert gas conveying a refrier'ant medium in gaseous phase,comprising forming a column of said absorbent, forming a propelledstream of said gaseous mixture by creating a pressure differentialtherein,

and bubbling a part only of said gaseous streamunder a pressurein a highpressure area of said gaseous stream into said absorbent column to Wealso wish to point out that either a single lift saidcolumn to anelevated position, and then spreading out said absorbent into a gravityactuated stream presenting an extended surface area to the gaseousstream whereby said refrigerant is absorbed thereby.

'7. The method of bringing an absorbent liquid into absorbing relationwith a dense inert gas conveying a refrigerant in gaseous phase,comprising forming a column of said absorbent, forming a propelledstream of said gaseous mixture by creating a pressurediiferentialtherein, bubbling a part of said gaseous stream under pressure in a highpressure area of said gaseous stream into said absorbent column to liftsaid column to an elevated position and then bringing the absorbentstream in-counterflow to but in intimate contact with the remaining partof the gaseous mixture stream whereby the refrigerant is absorbed.

8. In an absorption refrigeration system of the type using arefrigerant, an absorbent therefor,

and a dense inert gas, the combination of a boiler, an analyzercommunicating therewith, an absorber having at least a portion thereofabove said analyzer, an evaporator means providing'an inert gas circuitbetween said evaporator and said ababsorbent circuit to lift the liquidto the top ofthe absorber from whence it flows by gravity back to theanalyzer.

9. Absorption refrigeration; apparatus of the type employing arefrigerant, a solvent therefor, and an inert gas, said apparatuscomprising a refrigerant generator, a condenser, an evaporator, and anabsorber interconnected to provide a refrigerant circuit, an inert gascircuit, and a solvent circuit, means operable independently of saidevaporator to forciby circulate the inert gas in its circuit, and meansfor by-passing some of the circulating gas into said solvent circuit tocirculate the solvent.

' 10. Absorption refrigeration apparatus including a boiler, an absorberand an evaporator, means including the absorber and the evaporator forproviding an inert gas circuit therebetween, means including theabsorber and the boiler for providing an absorption fluid circuittherebetween, and common means operable independently of said evaporatorfor circulating the gas and the absorption fluid including means forby-passing some of the inert gas from its circuit intothe absorptionfluid circuit.

11. An absorber-boiler-analyzer assembly for a continuous absorptionrefrigeration apparatus comprising a boiler, an analyzer arranged at anangle to the horizontal and connected to the boiler, an absorber,absorption fluid conduits connecting the boiler, absorber and analyzerin circult and arranged to provide gravity flow of absorption liquidfrom the boiler to the absorber, and means for circulating theabsorption fluid through said circuit including a gas lift pump actuatedby a gas which is non-condensable at ambient temperature.

12. That improvement in the art of refrigeration by means of a,continuous absorption system of the type employing a refrigerant medium,an .absorbent therefor, and a dense inert gas which includes positivelycirculating weak absorption fluid into intimate absorbing relation witha stream of refrigerant laden inert gas whereby the refrigerant isabsorbed, returning the enriched absorbent to a high temperature zone bygravity whereby refrigerant is liberated, and returning weak absorbentfrom said high temperature zone to said absorption zone by passing apart only of said gas stream into a column of the weak fluid.

' 13. A boiler-absorber assembly for an absorption refrigerating systemcomprising a boiler, an analyzer, an absorber and an absorption solutionreservoir interconnected in circuit, said circuit including a twin gaslift pump operable to circulate absorption solution through the assemblyand connected to elevate liquid from the boiler to the absorber, saidreservoir being positioned intermediate the upper and lower extremitiesof said pump and connected to provide for the gravity return of enrichedabsorption solution to said analyzer.

14. An air cooled absorption refrigeration apparatus having anair-cooled condenser and an air cooled absorber of the inclined tubetype in which the absorption solution flows downwardly therethrough incounterflow t0 the refrigerant gas being absorbed, said apparatus havinga paratus having a boiler-analyzer assembly, and

an absorber connected in circuit therewith, said circuit including asolution reservoir and a gas lift pump device, said reservoir and pumpbeing so positioned that a desired liquid level is maintained in saidpump, said circuit also including a gas separation chamber into whichsaid pump discharges and located above the lower portion of the absorberwhereby the weak absorption solution flows from the boiler-analyzerassembly to the absorber and reservoir by gravity, and is thereafterelevated by the gas lift pump to the gas separation chamber from whichit returns to said analyzer by gravity.

16. That improvement in the art of refrigeration by means of anabsorption system having an absorption solution circuit and of the typecharged with a refrigerant, an absorbent medium therefor and an inertpressure equalizing medium which improvement comprises forciblycirculating the pressure equalizing medium through an absorption zoneand an evaporation zone,-and by-passing a portion thereof into a circuitcontaining the absorption solution to circulate the same simultaneouslywith the pressure equalizing medium.

17. That method of circulating the absorption solution in arefrigeration system of the type containing a refrigerant, an absorbentmedium therefor, and an inert pressure equalizing medium and of the typehaving a pressure equalizing medium circuit and an absorbent mediumcircuit, which method comprises forcibly circulating a principal streamof the inert pressure equalizing medium in its circuit, and diverting aportion thereof and bubbling it into absorption liquid in the absorptionmedium circuit to circulate the solution at a desired rate with respectto the principal stream of pressure equalizing medium.

18. That improvement in the art of refrigeration by means of a systemhaving a boiler, an absorber, conduits connecting the same in circuit,an inert gas circuit including said absorber therein, said system beingchargeable with a refrigerant, an absorbent medium therefor, and aninert pressure equalizing medium, said improvement comprising raisingthe pressure of a portion of said inert medium and conducting separateportions thereof under pressure into two interconnected columns ofabsorption medium in the absorption medium circuit to 'divide a streamof absorption medium flowing to said columns into a plurality ofstreams.

19. A boiler-absorber assembly for an absorption refrigerator comprisinga boiler having an analyzer, an absorberconstructed and arranged forgravity flow of absorption liquid therethrough, conduits connecting saidboiler, analyzer and absorber in circuit, said conduits including'a gaslift pump located in a portion thereof normally containing absorptionliquid, and means for circulating a main stream of inert non-condensinggas through the absorber, and means for diverting a portion only of saidgas and introducing the same below the liquid level in said pump tocirculate the absorption liquid at the desired rate for the efllcientoperation of said boiler-analyzer assembly.

20. A boiler-absorber assembly for an absorption system comprising aboiler, an analyzer therefor, an absorber and a solution reservoirinterconnected in circuit, said circuit including a twin gas lift pump,said reservoir being positioned intermediate the upper and lowerextremities of said pump, and means for introducing a non-condensablegas into said pump below the static liquid level therein to circulateabsorption liquid in said boiler-absorber, assembly.

21. Absorption refrigeration apparatus of the type employing arefrigerant, a solvent therefor, and an inert gas, said apparatuscomprising a refrigerant-generator, a condenser, an evaporator, and anabsorber interconnected to provide a refrigerant circuit, an inert gascircuit, and a which it may flow by gravity to the boiler assembly.

24. In combination, anabsorption refrigeration system including a boilerassembly, an absorber'having its upper end located below an upperportion of said boiler assembly, an evaporator, conduits interconnectingsaid evaporator and said absorber for the circulation of an inert mediumtherebetween, conduits interconnecting said boiler assembly and saidabsorber for the circulation of absorption medium therebetween thearrangement being such that weakened absorption solution flows to andthrough said absorber by gravity, means for circulating the inert mediumin its circuit under pressure, means connected in parallel with aportion of said inert' medium circuit and communicating with a high anda low pressure area therein, said parallel connection having a portionin common with said absorption solution circuit and constructed andarranged to bubble inert medium into the absorption solution to elevatethe solution to a point from which it returns to the boiler assembly bygravity flow.

25. In combination, an absorption refrigeration system including aboiler, an analyzer communicating therewith, a tubular, air-cooled,inclined absorber assembly connected in a closed absorption solutioncircuit with said boiler and said analyzer and so positioned withrespect thereto that weakened absorption solution flows by gravity tothe upper portion of the absorber,

"an evaporator, conduits interconnecting said solvent circuit, meansoperable to create a substantlal pressure differential in the inert gascircuit to circulate the gas therethrough, and means for by-passing someof the circulating gas at a raised pressure into said solvent circuit tocirculate the solvent in its circuit.

22. Absorption refrigeration apparatus including a boiler, an absorberand an evaporator, means providing an inert gas circuit between theevaporator and absorber, means providing an absorption fluid circuitbetween the boiler and the absorber, and common means for raising thepressure of the inert gas in its circuit for circulating the gas in itscircuit and for circulating the absorption fluid in its circuit, saidcommon means including means for by-passing some of the inert gas fromits circuit and at the raised pressure existing therein and bubbling itinto the absorption fluid circuit.

23. An absorption refrigeration apparatus including a boiler assembly, atubular air-cooled absorber arranged for gravl flow of absorption liquidtherethrough, said fixorber being arranged below the upper portio .ofsaid boiler assembly and connected to said boiler for the gravity flowof weak absorption solution thereto from the boiler, and power drivenmeans for introducing a dense gas into a body of enriched absorptionliquid obtained from the lower end of said absorber and elevating thesame to a point from evaporator and absorber and providing an inertmedium circuit therebetween, means providing a local circuit including aportion of the inert medium circuit and a portion of the absorptionsolution circuit, means for creating a pressure differential in theinert medium in that portion of the inert medium circuit included insaid lastmentioned local circuit, the arrangement being such that saidpressure diiferential causes inert medium to be bubbled into enrichedabsorption solution to circulate the same between the boiler, analyzerand absorber.

26. In combination, an absorption refrigeration system including aboiler, an evaporator, an absorber, conduits interconnecting saidevaporator and absorber to provide an inert medium circuit therebetween,conduits interconnecting said boiler and absorber to provide anabsorption solution therebetween, means for creating a pressuredifferential in said inert medium circuit to circulate a major portionof the inert medium therein, means connected in parallel with a portionof said inert medium circuit between points of differing inert mediumpressures, said means having a portion in common with a part of saidabsorption solution circuit and being arranged to introduce inert mediuminto said solution.

27. In combination, an absorption refrigeration system including aboiler, an absorber having a plurality of branches, an evaporator,conduits providing a closed inert medium circuit including saidevaporator and said absorber branches, means for creating a pressuredifferential in said circuit to circulate the inert medium therethrough,means interconnecting said boiler and said absorber branches to providean absorption solution circuit therebetween, and means forming a part ofsaid absorption solution circuit and utilizing inert medium withdrawnfrom a high pressure area in said inert medium circuit to divideabsorption solution between said absorber branches.

cuit to circulate the gas therethrough, and means interconnecting saidinert gas circuit and said solution circuit and utilizing said pressuredifferential to promote the circulation of the absorption solution inthe solution circuit.

29. An absorption refrigeration apparatus including a generator, acondenser, an evaporator and an absorber connected in circuit, a gasimpeller for circulating inert gas between the ab sorber and theevaporator, a gas lift pump for circulating absorption liquid betweenthe absorber and the generator, means for supply inert gas from thedischarge side of said gas impeller to the gas lift pump to actuate thesame, and means for raising the static level of the liquid pressurethrough said vessels. a plurality of liquid elevating conduits connectedto said vessels, common means for supplying liquid to the lower ends ofsaid conduits, and common means for directing at least a. portion of thegas circulated through said vessels into said elevating columns belowthe liquid level therein, the arrangement being such that gas dischargedthrough said elevating conduits into said vessels immediately joins themain stream of gas exiting from said ves sels.

33. In a continuous absorption refrigerating system having a pluralityof interconnected parts in open communication, an arrangement forlifting liquid from one level to another therein, said arrangementincluding an unobstructed U-tube, means for supplying liquid to thebottom of said U-tube, means for building up agas pressure in one partof said system and means providing unobstructed communication betweensaid part of the system containing gas at said higher pressure ";.andboth legs of said U-tube, the arrangement being such that liquid isalternately discharged in said gas lift pump when the apparatus isopcrating above the static level of the liquid in the pump when theapparatus is not operating.

30. An absorption refrigeration apparatus including a refrigerantgenerator, an evaporator, and an absorber, an inert gas circuitconnecting the evaporator and the absorber, an'absorption' solutioncircuit connecting the generator and the absorber, a gas impeller forcirculating the inert gas in its circuit, a. gas lift pump forcirculating the absorption solution in its circuit, means for supplyinginert gas from said inert gas circuit to said gas lift pump to actuatethe same, and means connected between said inert gas circuit and saidabsorption solution circuit for depressing the liquid level in one partof said absorption solution circuit to raise the static liquid level insaid pump.

31. In a fluid system having a plurality of gas and liquid circuits, thecombination of a plurality of vessels through which the gas and liquidtravel in contact, means for circulating a gas under pressure throu hsaid vessels, a plurality of liquid elevating conduits connected to saidvessels, common means for supplying liquid to the lower ends of saidconduits, and common means for directing at least a portion or the gascirculated through said vessels into said elevating columns below theliquid level therein.

32. In a fluid System having a plurality of gas and liquid circuits, thecombination of a plurality of vessels through which the gas and liquidtravel in contact, means for circulating a gas under from the upper endof one of the legs of said U-tube and then from the upper end of theother leg of the U-tube.

34. A fluid system including means for placing a gas under pressure, apumping structure including a plurality of unobstructed pumpingpassageways and a connecting passageway in open communication with eachof said pumping passageways, a source of liquid to be pumped, meansproviding open communication between said source of liquid to be pumpedand said pumping structure, and means providing open communicationbetween said gas under pressure and each of said pumping passagewaysadjacent the communicating portion thereof.

35. In an absorption refrigerating system using inert gas, a pair ofliquid receiving sections, a combined gas circulator and liquidcirculator comprising a power operated gas pump, a twin gas lift liquidpump connected to discharge into said sections, and means for conductinggas from said gas pump to said twin gas lift pump.

36. In an absorption refrigerating system using inert. gas, a pair ofliquid receiving sections, a combined gas circulator and liquidcirculator comprising a power operated gas pump, a twin gas lift liquidpump connected to discharge into said sections, means for conductin gasfrom said gas pump to said twin gas lift pump, said twin lift liquidpump consisting of an unobstructed U- tube having means for supplyingliquid to the bottom thereof, the arrangement being such that liquid isdischarged from the legs of said U-tube alternately.

' CURTIS C. COONS.

RUDOLPH S. NELSON.

